Avalanche Forecast

Issued: Feb 10th, 2019 5:28PM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is low. Known problems include Wind Slabs.

Avalanche Canada cgarritty, Avalanche Canada

Stability is improving, but heavy wind effect has made alpine travel an unappealing prospect. Seek out what sheltered snow remains for the safest, best skiing and riding.

Summary

Confidence

High -

Weather Forecast

Sunday night: Clear. Strong to extreme east winds.Monday: Sunny. Moderate to strong east winds. Alpine high temperatures around -15.Tuesday: Sunny. Strong northeast winds easing to light over the day. Alpine high temperatures around -13.Wednesday: A mix of sun and cloud. Light variable winds. Alpine high temperatures around -9.

Avalanche Summary

On Friday, a skier triggered a small (size 1) soft wind slab avalanche on a north aspect at 1550 m near Mt Hadden.A small (size 1) storm slab was triggered by a skier in the southeast of the region on Thursday. This occurred on a steeper (38 degree), convex, north-facing slope at 1300 metres. Although small, it highlights the potential for smaller, older storm slabs to react to skier triggering on suspect features.Reports from Wednesday showed explosives control yielding mainly small (size 1) wind slab releases in the Shames area. Several other recent small (size 1.5) natural wind slab releases were observed in alpine features in the Legate Peak area.

Snowpack Summary

In most areas, the upper snowpack is composed of successive layers of aging, wind affected storm snow layers. The top layer of this snow has been faceting (becoming sugary) under the influence of recent cold temperatures at all elevations. With recent southeast and northeast winds, thin wind slabs have developed in the lee of ridgecrests and other wind exposed features. Sheltered areas at lower elevations may still hold pockets of around 40 cm of low density snow which will overlie a thick melt-freeze crust at and below treeline.In the south of the region, the remainder of the snowpack is well-settled.Around Bear Pass and in the north of the region, there is a weak layer of feathery surface hoar crystals about 50 cm deep. This layer is likely most prominent in sheltered and shaded areas. Also in the north, a few weak layers may still exist within the middle and lower half of the snowpack. These include another layer of surface hoar around 70 to 100 cm deep and a layer of sugary faceted snow around 200 cm deep. These layers are a concern in thinner snowpack areas at higher elevations, where thicker, bridging layers of old storm snow and crust may be absent.

Problems

Wind Slabs

An icon showing Wind Slabs
Outflow winds from the southeast and northeast have been scouring surface snow and packing it into thin wind slabs on lee slopes. Older, larger slabs are trending toward stabilizing but may react to human triggers on steeper, unsupported features.
Watch for whumpfing, hollow sounds, and shooting cracks.Look for patterns of wind loading as you transition into wind affected terrain.Be careful around wind loaded pockets near ridge crests and roll-overs.

Aspects: North, South, South West, West, North West.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 1.5

Valid until: Feb 11th, 2019 2:00PM